Vehicle internal-combustion engine fuel control and signal device

ABSTRACT

A control for preventing damage to an internal-combustion engine due to extended operation at excessive temperatures where the engine speed varies according to flow of fuel thereto. The control includes a fuel-limiting solenoid valve which controls the flow of fluid to the engine and which has a plunger movable from a first position permitting unobstructed fuel flow to a second position causing fuel flow reduction to a preset reduced amount causing engine speed reduction sufficient to reduce the operating temperature thereof, the valve having a winding which, when deenergized, permits movement of the plunger from the first position to the second position. Switch means is connected in a circuit with the winding for controlling the energization thereof and is responsive to the operating temperature of the engine. This switch means operates to cause deenergization of the winding when the engine operating temperature exceeds a preset level, thereby protectively reducing the engine speed to reduce its operating temperature.

illnitee States Fatent Goodman [72] Inventor: Johnny Goodman, GraniteCity, 111.

{73] Assignee: Joseph .1. Bristow, East Carondelet, 111. a

part interest [22] Filed: Jan. 25, 1971 [21] Appl. No: 109,392

[4 1 Feb. 29, 1972 Primary Examiner-Alvin H. Waring Attorney-Koenig,Senniger, Powers & Leavitt [5 7] ABSTRAQT A control for preventingdamage to an intemal-combustion engine due to extended operation atexcessive temperatures where the engine speed varies according to flowof fuel thereto. The control includes a fuel-limiting solenoid valvewhich controls the flow of fluid to the engine and which has a plungermovable from a first position permitting unobstructed fuel flow to asecond position causing fuel flow reduction to a preset reduced amountcausing engine speed reduction sufficient to reduce the operatingtemperature thereof, the valve having a winding which, when deenergized,permits movement of the plunger from the first position to the secondposition. Switch means is connected in a circuit with the winding forcontrolling the energization thereof and is responsive to the operatingtemperature of the engine. This switch means operates to causedeenergization of the winding when the engine operating temperatureexceeds a preset level, thereby protectively reducing the engine speedto reduce its operating temperature 10 Claims, 4 Drawing Figures [52}US. Cl .340/53, 180/82 [51] Int. Cl .3601 M01), G08b 21/00 [58] FieldoiSearch ..340/52,53,57; 180/82 [56] References Cited UNlTED STATESPATENTS 3,302,171 1/1967 Sensing ..340/57 3,546,667 10/1968 Thomas..340/53 3,431,779 3/1969 Wilken et al. ..340/52 X 3,509,529 4/1970Utter ..340/52 FROM FUEL C SUPPLY wo WARNING LIGHT OIL PRESSURE SHEET 1[IF 2 on. TEMP.

PATENTEUFEB 2 9 I972 F I G. 1

FROM FUEL &: SUPPLY FIGZ 25 TO FUEL SUPPLY WARNING Oi L TEMP.

PMENTEBFEBZS m2 3,646,513

SHEET 2 BF 2 FIGS FE G4 VEHICLE INTERNAL-COMBUSTION ENGINE FUEL CONTROLANEB SEGNAL DEVKCE BACKGROUND OF THE INVENTION This invention relatesgenerally to automotive fuel controls and more particularly to a fuelcontrol for preventing damage to an internal-combustion engine.

In the operation of trucks, such as large, long-haul truck tractorshaving diesel engines, there is a serious problem in the truckingindustry of damage to such engines which results from extended operationat excessive temperatures. It often happens that a truck engine will beoperated with greater power output and greater speed than is prudent,typically with indifference or deliberate disregard to the enginetemperature. For example, the truck may be driven for long periods withwideopen throttle. In truck engines having exhaustdriven turbochargers,an increase in exhaust temperature will provide even greater availablepower. A driver may therefore deliberately mrmit the engine temperatureto become excessive for the purpose of obtaining greater power. Inaddition to these kinds of manhandling of an engine, there is awidespread problem caused by drivers who modify the fuel controls of anengine, such as by restricting the fuel return line for a diesel engine,in order to provide greater power output and greater engine speed. Inany case, extended operation of the engine at the resultant excessivetemperatures produces serious damage to the engine, such as crackedpistons, broken piston rings, and the like.

l-leretofore, there has been no efiective means for preventing thermaldamage to truck engines resulting from extended operation at excessivetemperatures. Examples of the prior art may be found in US. Pat. Nos.2,171,401, 2,629,047, 2,692,980, 2,870,753, and 3,431,555.

BRIEF DESCRIPT ION OF THE INVENTION Among the several objects of theinvention may be noted the provision of a fuel control for preventingdamage to an internal-combustion engine due to extended operation atexcessive temperatures; the provision of such a control which isparticularly useful in conjunction with diesel truck engines; theprovision of such a control which is relatively tamperproof; theprovision of such a control which is fail-safe in operation; theprovision of such a control which is highly reliable and long lasting inoperation; and the provision of such a control which is simply andeconomically constructed and installed. Other objects and features willbe in part apparent and in part pointed out hereinafter.

Briefly, a control of the present invention is adapted to prevent damageto an internal-combustion engine due to extended operation at excessivetemperatures where the engine is of the type having a speed which variesaccording to flow of fuel thereto. The control comprises a fuel-limitingsolenoid valve for controlling the flow of fuel to the engine, the valvehaving a fuel control plunger movable from a first position permittingunobstructed flow of fuel to the engine to a second position causingreduction of the flow of fuel to a preset reduced amount causingreduction in engine speed by an amount sufficient to reduce theoperating temperature thereof. The solenoid valve includes a windingadapted when energized to maintain the plunger in said first positionand when deenergized to permit movement of the plunger to said secondposition. The control further includes switch means connected in acircuit with said winding for controlling the energization thereof. Thisswitch means is responsive to the operating temperature of the engineand is operative to cause deenergization of the valve winding when theoperating temperature exceeds a preset level. In this way, the speed ofthe engine is protectively reduced to reduce the operating temperaturethereof in response to excessive temperature. In a preferred embodiment,the control further comprises second switch means connected in saidcircuit with the winding for controlling the energization thereof. Thesecond switch means is responsive to the pressure of lubricant for theengine and operative to cause deenergization of the winding when thelubricant pressure falls below a preset level. Accordingly, the speed ofthe engine is also protectively reduced in response to reduced lubricantpressure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a pictorial illustration ofa fuel control of the present invention shown for use with a dieselengine of the type employed in trucks;

FIG. 2 is a schematic circuit diagram of the present control;

FIG. 3 is a vertical cross section of a fuel-limiting solenoid valve ofthe present control; and

FIG. 3 is a horizontal cross section of the fuel-limiting solenoid valvetaken along line 41-4 of FIG. 3.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,and more particularly to FIGS. 1 and 2, a fuel-limiting solenoid valveof the present invention, designated generally ll, is installed in thefuel input line 13 leading from a fuel supply tank to the fuel injectionpump 15 of a diesel truck engine 17. Engine 17 is of the type of enginewhose speed varies according to flow of fuel thereto. Thus the enginespeed may be throttle controlled through operation of injection pump l5by varying the amount of fuel delivered by the engine fuel injectors. Aswill be clear, however, the engine speed and thus the amount of powerthe engine can deliver may be reduced by restricting the flow of fueldelivered by line 13 by operation of solenoid valve 1 ll.

Referring to FIG. 2, solenoid valve llll includes a fuel control plunger19 adapted to be operated by a solenoid winding 21. Plunger 19 ismovable from a first position, permitting unobstructed flow of fuel tothe engine fuel pump 15 through line 13 to a second position asillustrated. In this second position, plunger 19 causes reduction of theflow of fuel to a preset reduced amount determined by an adjusting screw23. This reduced amount is predetermined to be sufficient to cause theengine power to diminish, thereby to reduce the operating temperature ofengine 17 even if the truck driver should deliberately attempt tomaintain full throttle operation, et cetera. Winding 21 is adapted whenenergized to maintain plunger 19 in the first position for unobstructedfuel flow and when deenergized to permit movement of plunger 19 underbias of a compression spring 25 to the second position.

Connected in a series circuit to one side of winding 2ll, the other sideof which is grounded, are the normally closed contacts 27 of an oiltemperature switch 23, and the normally open contacts 31 of an oilpressure switch 33. This series circuit is adapted to be connected tothe hot side of a power source constituted by the usual truck storagebattery 35 by the closing of one set of contacts 37 of the usualkey-operated main or master switch 39 of the truck, which is manuallyoperated to close contacts 37 for normal operation of the truck.

Both oil temperature switch 29 and oil pressure switch 33 may bephysically mounted on engine 17 and connected to the so-called oilgallery thereof. Oil temperature switch 29 constitutes switch meansresponsive to the engine operating temperature, and contacts 29 thereofare adapted to open, thereby deenergizing winding 21, when the enginetemperature exceeds a preset level, e.g., an oil temperature of 235 F.Oil pressure switch 33 constitutes switch means responsive to the engineoil pressure, and contacts 31 thereof are adapted to remain open for oilpressures below a preset level, e.g., l5 p.s.i., but to close at orabove that level.

From the foregoing it will be seen that so long as the oil temperatureis below the operating value for switch 29, i.e., 235 F and the oilpressure is above the operating value for switch 33, a circuit forenergizing winding 21 will be completed, assuming key switch contacts 37are closed, from battery 35, through contacts 37, through contacts 27and 31, and winding 21. Plunger l9 thus will be maintained in the firstposition providing unobstructed fuel flow for normal engine operation.

However, heating of the engine to the preset. value, e.g., of 235 R,will open contacts 27 and thereby deenergize winding 21. Alternatively,a reduction in lubricant pressure, e.g., to less than the preset levelof 15 psi, will open contacts 31 and deenergize winding 21. Such an oilpressure reduction may be caused, for example, either by excessive oiltemperature or some other failure in the oil system, such asinsufficient oil. in any case, operation of either oil temperatureswitch 29 or oil pressure switch 33 will cause plunger 19 to restrictthe flow of fuel and thereby protectively reduce the speed of theengine, so as to reduce its operating temperature.

It will be noted that upon startup of the engine, oil pressure is notdeveloped until the engine attains normal running speed. Hence, contacts31 of oil pressure switch 33 remain open until running speed isattained. Accordingly, at engine startup, plunger 19 is in the fuelflow-reducing position. However, this does not prevent the engine frombeing started since less fuel is required for starting than running.Moreover, this is advantageous in preventing the engine from beingoverspeeded prior to buildup of adequate lubricant pressure. That is,fuel flow will be limited until contacts 3 of the oil pressure switchclose. Of course, a bypass switch could be connected across contacts 31,if desired, for use in starting the engine.

A driver-warning provision of the present invention includes a furtheroil temperature switch 4i. having a set of normally open contacts 43which are connected with a conventional signal or warning light 45 inseries circuit between ground and the junction of switch contacts 37with pressure switch contacts 31. Signal light 45 is positioned forbeing observed by the truckdn'ver. Oil temperature switch 41 is selectedto have an operating temperature, at which contacts 43 thereof areadapted to close, which is a few degrees less than the operatingtemperature of temperature switch 29. For example, contacts 43 may closeat about 225 F. It has been found that if the operating temperature ofthe truck engine starts to become excessive, there will be a short timelag, of about a minute, for example, before the temperature can climbthe last few degrees (i.e., F. in this case). Accordingly, signal light45 will be energized to signal the driver that the temperature hasexceeded 225 F. (i.e., the present operating temperature of switch llThe driver will then have warning that, if the engine continues to beoperated with too much throttle, etc., solenoid valve 11 will shortly beoperated by switch 2) to cause an engine-speed reduction. So warned, thedriver may reduce speed or shift to a lower gear and thus avoid a fuelreduction. As will be seen, operation of key switch 39 is also adaptedto connect this warning circuit to battery 35 for normal operation.

Referring to FIGS. 3 and d, fuel-limiting solenoid valve 111 is shown tocomprise a cylindrical valve body or block 47 having a drilledconcentric cylindrical bore 49 in which plunger 19, also cylindrical, isaxially slidable between its aforesaid first and second positions.Plunger is shown in its second position. A cylindrical sleeve Slincludes an annular flange 53 threaded into a concentric recess 54 atthe top of body 47 and extends upward from body 47. Sleeve 53 alsoincludes a drilled tubular concentric recess 55 providing an extensionof bore .9. Compression spring 25 is fitted into a tubular concentricrecess 57 at the upper end of plunger 19 and bears against the ends ofrecesses 55 and 57 for biasing plunger 19 for downward movement which islimited by a setscrew 59 screwed into block 47. Setscrew 59 bearsagainst the lower surface of plunger 19 when the latter is in thefuel-limiting second position shown. A locknut 61 is screwed into atapped recess 63 for locking setscrew 59 in position. Lock nut 61 may besafety wired in position and a seal 65 applied to the safety wire. Atruck driver or other person is thus prevented from tampering withsetscrew 55 a broken wire or seal being evidence of such tampering.

A thin, cylindrical metal cap 67 is fitted over the upper end of block47. The upper end of sleeve 5! is threaded and extends through anaperture 69 in the top of cap 67. A knurled, threaded collar Ill isscrewed onto this threaded portion of sleeve 5i to secure cap 67.Winding 21 is axially wound in the annular space 73 between sleeve 51and cap 67.

Valve block 47 includes a fuel inlet port 75 and a fuel outlet port 77both communicating with bore 49. Fuel outlet port 77 is substantially inregistry with fuel inlet port 75. it will be understood that fuel line13 is connected to inlet port 75 and outlet port 75 is connected by ashort fuel line to fuel pump l5,

each by suitable compression fittings screwed into respective drilledrecesses 79 and 8H. Plunger 19 is provided with an an,- nular groove 83.When plunger 19 is in its first position for unobstructed fuel flow,i.e., is magnetically attracted to its uppermost position within bore 49(as viewed in FIG. 3) by winding 21, groove 33 is aligned generally withfuel inlet and fuel outlet ports 75 and 77. However, in its second positon (illustrated) with winding 2E deenergized, plunger 19 moves againstsetscrew 59 so that groove 83 is moved out of alignment with inlet andoutlet ports 75 and 77 by a preset distance determined by setscrew 59,thereby causing reduced fuel flow between these inlet and outlet ports.Thus setscrew 59 pro vides means for adjustably limiting movement ofplunger 19.

A fuel pressure test port 85 of smaller diameter than ports 75 and 77but in registry with the latter ports may also be provided asillustrated to permit a pressure gauge to be connected at a threadedrecess 37. This permits precise calibration of the position of plunger19 by adjustment of setscrew 59. Recess 87 may be plugged aftercalibration with a nipple.

It should be observed that a control of the present invention issubstantially fail-safe. if any of the components fail or power from thebattery is interrupted (as by a driver's intentional cutting of theleads), winding 2 of solenoid valve ill will be deenergized, causingplunger 19 to move to its fuel-limiting position.

In order to provide even greater assurance against unauthorizedtampering with the circuit, the circuit lead, designated 89 in FIG. 2,extending from oil temperature switch 29 and connecting its contacts 27to winding 211, is provided with a shield 53. Shield 91 may comprisemetal tubing or suitable braided or armored flexible tubing. Shield Qllprevents tampering not only by making it difficult to gain access tolead 89, but also by giving the appearance of an oil line or the like.This causes the driver or other would-be tamperer to believe thatcutting or removing the shield would release oil, et cetera. This oilline appearance may be enhanced by employing cornpression-type orknurled fittings 93 and 95 at the ends of shield 9E.

in view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

l. A control for preventing damage to an intemal-combustion engine dueto extended operation at excessive temperatures, said engine having aspeed which varies according to flow of fuel thereto, said controlcomprising:

a fuel-limiting solenoid valve for controlling the flow of fuel to saidengine, said valve having a fuel control plunger movable from a firstposition permitting unobstructed flow of fuel to said engine to a secondposition causing reduction of the flow of fuel to a preset reducedamount causing reduction in engine speed by an amount sufficient toreduce the operating temperature thereof, said valve further including awinding adapted when energized to maintain said plunger in said firstposition and when deenergized to permit movement of said plunger to saidsecond position; and

first switch means connected in a circuit with said winding forcontrolling the energization thereof, said switch means being responsiveto the operating temperature of the engine and operative to causedeenergization of said winding when the operating temperature exceeds apreset level whereby the speed of the engine is protectively reduced toreduce the operating temperature thereof in response to excessivetemperature.

2. A fuel control as set forth in claim ll further comprising secondswitch means connected in said circuit with said winding for controllingthe energization thereof, said second switch means being responsive tothe pressure of lubricant for the engine and operative to causedeenergization of said winding when the lubricant pressure falls below apreset level whereby the speed of the engine is also protectivelyreduced in response to reduced lubricant pressure.

3. A fuel control as set forth in claim 1 wherein said plunger is biasedfor movement from said first position toward said second position.

4. A fuel control as set forth in claim 1 wherein said plunger iscylindrical, said valve further including a cylindrical bore in whichsaid plunger is axially slidable between said first and secondpositions, a fuel inlet port communicating with said bore, a fuel outletport communicating with said bore and substantially in registry withsaid inlet port, said plunger having an annular groove aligned generallywith said inlet and outlet ports when said plunger is in said firstposition and which is moved out of alignment by a preset distance tocause said reduction in the flow of fuel to said engine when saidplunger is moved to said second position.

5. A fuel control as set forth in claim 4 wherein said valve furtherincludes means for adjustably limiting movement of said plunger toestablish said preset distance.

6. A fuel control as set forth in claim 1 wherein first switch meansincludes a normally closed set of contacts connected in series with saidwinding and adapted to open when the operating temperature exceeds thepreset temperature valve, and said second switch means includes anormally open set or'contacts also connected in series with said windingand adapted to be closed by lubricant pressure above the preset pressurevalve.

7. A fuel control as set forth in claim 6 wherein a circuit lead extendsfrom the set of contacts of said first switch to said winding andfurther comprising means for shielding said circuit lead thereby toprevent tampering therewith.

8. A fuel control as set forth in claim It further comprising signalmeans and further switch means connected in a further circuit with saidsignal means, said further switch means being responsive to theoperating temperature of said engine and being operative to causesignalling operation of said signal means when the operating temperatureexceeds a further preset level less than the preset level causingoperation of said first switch means, thereby to give warning prior toengine speed reduction resulting from operation of said first switchmeans.

9. A fuel control as set forth in claim 8 wherein said signal meanscomprises a warning light and said third switch means includes anormally open set of contacts connected in series with said warninglight and adapted to close for energizing said light when the operatingtemperature exceeds said further preset level.

10. A fuel control as set forth in claim 8 further comprising manuallyoperable switch means for connecting a power source in the circuit withsaid winding and in said further circuit with said signal means.

1. A control for preventing damage to an internal-combustion engine dueto extended operation at excessive temperatures, said engine having aspeed which varies according to flow of fuel thereto, said controlcomprising: a fuel-limiting solenoid valve for controlling the flow offuel to said engine, said valve having a fuel control plunger movablefrom a first position permitting unobstructed flow of fuel to saidengine to a second position causing reduction of the flow of fuel to apreset reduced amount causing reduction in engine speed by an amountsufficient to reduce the operating temperature thereof, said valvefurther including a winding adapted when energized to maintain saidplunger in said first position and when deenergized to permit movementof said plunger to said second position; and first switch meansconnected in a circuit with said winding for controlling theenergization thereof, said switch means being responsive to theoperating temperature of the engine and operative to causedeenergization of said winding when the operating temperature exceeds apreset level whereby the speed of the engine is protectively reduced toreduce the operating temperature thereof in response to excessivetemperature.
 2. A fuel control as set forth in claim 1 furthercomprising second switch means connected in said circuit with saidwinding for controlling the energization thereof, said second switchmeans being responsive to the pressure of lubricant for the engine andoperative to cause deenergization of said winding when the lubricantpressure falls below a preset level whereby the speed of the engine isalso protectively reduced in response to reduced lubricant pressure. 3.A fuel control as set forth in claim 1 wherein said plunger is biasedfor movement from said first position toward said second position.
 4. Afuel control as set forth in claim 1 wherein said plunger iscylindrical, said valve further including a cylindrical bore in whichsaid plunger is axially slidable between said first and secondpositions, a fuel inlet port communicating with said bore, a fuel outletport communicating with said bore and substantially in registry withsaid inlet port, said plunger having an annular groove aligned generallywith said inlet and outlet ports when said plunger is in said firstposition and which is moved out of alignment by a preset distance tocause said reduction in the flow of fuel to said engine when saidplunger is moved to said second position.
 5. A fuel control as set forthin claim 4 wherein said valve further inclUdes means for adjustablylimiting movement of said plunger to establish said preset distance. 6.A fuel control as set forth in claim 1 wherein first switch meansincludes a normally closed set of contacts connected in series with saidwinding and adapted to open when the operating temperature exceeds thepreset temperature valve, and said second switch means includes anormally open set of contacts also connected in series with said windingand adapted to be closed by lubricant pressure above the preset pressurevalve.
 7. A fuel control as set forth in claim 6 wherein a circuit leadextends from the set of contacts of said first switch to said windingand further comprising means for shielding said circuit lead thereby toprevent tampering therewith.
 8. A fuel control as set forth in claim 1further comprising signal means and further switch means connected in afurther circuit with said signal means, said further switch means beingresponsive to the operating temperature of said engine and beingoperative to cause signalling operation of said signal means when theoperating temperature exceeds a further preset level less than thepreset level causing operation of said first switch means, thereby togive warning prior to engine speed reduction resulting from operation ofsaid first switch means.
 9. A fuel control as set forth in claim 8wherein said signal means comprises a warning light and said thirdswitch means includes a normally open set of contacts connected inseries with said warning light and adapted to close for energizing saidlight when the operating temperature exceeds said further preset level.10. A fuel control as set forth in claim 8 further comprising manuallyoperable switch means for connecting a power source in the circuit withsaid winding and in said further circuit with said signal means.